For forty-two years (1880–1923), Hirsch served as the rabbi of Chicago Sinai Congregation, one of the oldest synagogues in the midwest. At this post, he became well known for an emphasis on social justice. From Chicago Sinai's pulpit, he delivered rousing sermons on the social ills of the day and many Chicagoans, Jew and gentile alike, were in attendance.

He was an influential exponent of advanced thought and Reform Judaism. He edited Der Zeitgeist (Milwaukee) (1880–82) and the Reform Advocate (1891–1923). He also edited the Department of the Bible of the Jewish Encyclopedia and contributed feminist articles to The American Jewess. He also wrote studies of the historical relationship of Judaism and Christianity, including appreciations of its founding figures Jesus and Paul.[1]